A surgical instrument for ligating haemorrhoids is disclosed in European patent EP 0310582 B1, the contents of which are incorporated herein by reference. This surgical instrument, which will be referred to herein as a “surgical instrument of the type defined”, includes an inner front cylinder with the elastic cord stretched around its front end and an outer discharge cylinder displaceably arranged on the inner front cylinder to push the elastic cord off the inner front cylinder to close around the stem of a haemorrhoid when inserted in the inner front cylinder.
In its normal rest or contracted condition the generally circular elastic cord is of considerably smaller diameter than the external diameter of the inner front cylinder. The elastic cord is mounted on the inner front cylinder by means of a conical adaptor of circular cross-section having a larger rear end which makes a push fit in the inner front cylinder. The adaptor is tapered forwardly to its pointed front end which fits into the elastic cord when in its rest condition. The cord is then pushed or rolled by hand along the adaptor on to the inner front cylinder by the user, usually the surgeon. Difficulties arise because the elastic cord is small and the user has to wear gloves as protection against infection. This is especially true when the user has to perform several consecutive ligations.
It is an aim of the invention to alleviate the above-mentioned difficulties.